Winn Alice A
Department of Biological Science, Florida State University, Tallahassee, Florida, 32306-2043.
Evolution. 1996 Jun;50(3):1111-1118. doi: 10.1111/j.1558-5646.1996.tb02351.x.
Recent studies of evolution in heterogeneous environments have concentrated on the role of coarse-grained environmental variation. Here I explore the potential for a modular organism to adapt to fine-grained environmental variation through within-individual variation among modules. I describe the pattern of variation among leaves of single individuals and report results of initial analyses of genetic variation for within-individual variability in leaf traits and of genetic correlations that could influence the rate of further evolution of within-individual variation of these traits. Plants from 24 paternal half-sib families were raised in growth chambers, and five traits were measured for two leaves produced by each plant. Four of the five traits differed significantly between sampling times. Genetic analyses revealed significant additive genetic variation for within-individual variation in several traits. Estimates of family mean correlations between traits expressed at different times suggest few relationships that would be expected to impede response to selection for changes in the pattern of within-individual variation in leaf traits. These results support the possibility that within-individual variation could evolve as an adaptive response to fine-grained environmental variation and suggest a need for further investigation to improve understanding of evolution in heterogeneous environments.
近期关于异质环境中进化的研究主要集中在粗粒度环境变异的作用上。在此，我探讨了模块化生物体通过模块间个体内变异来适应细粒度环境变异的潜力。我描述了单个个体叶片间的变异模式，并报告了对叶片性状个体内变异性的遗传变异以及可能影响这些性状个体内变异进一步进化速率的遗传相关性进行初步分析的结果。来自24个父本半同胞家系的植株在生长室中培育，对每株植物产生的两片叶子测量了五个性状。五个性状中的四个在采样时间之间存在显著差异。遗传分析表明，几个性状的个体内变异存在显著的加性遗传变异。对不同时间表达的性状之间的家系平均相关性估计表明，预计很少有关系会阻碍对叶片性状个体内变异模式变化的选择响应。这些结果支持了个体内变异可能作为对细粒度环境变异的适应性反应而进化的可能性，并表明需要进一步研究以增进对异质环境中进化的理解。
